Wally,
A second axle gives you an obvious safety factor, but it is also two more 
tires and bearing sets to take care of. Also, the turning radius which you 
have been accustomed to with the single axle trailer goes out the window. 
Learning to back up with two axles will take a little getting used to. The 
single axle trailer turns on a dime where the dual axle takes a larger radius 
turn.

Rummy